The present invention relates to methods and apparatus suitable for use in access control. More particularly, but not exclusively, the invention relates to methods and apparatus for controlling and monitoring entry into secure areas.
Many factories use processes controlled by machines. Many of these processes are fully automated and require only a minimal amount of human interaction, often for the purpose of maintenance. Often a factory has many items of machinery operating in a single area of a factory. Within a single area, each item of machinery may be housed in a respective cell to prevent unauthorised access to particular machinery and to increase safety. If particular machinery in a cell breaks down and requires human interaction, a person is able to attend to that machinery without shutting down other machinery in a factory area which can continue to operate normally within respective other cells.
Access to a cell may be restricted by an access control system such that only those people who may require access are provided with access. A known access control system uses a lock which requires an access code to be provided for entry to a cell. The access control system is arranged such that machinery within the cell is stopped or placed into a safe mode before access to the cell is allowed. When a user enters an access code the access control system does not allow access to the cell until the machinery has been stopped or placed in a safe mode. The person is then able to attend to the machinery safely.
While the known systems described above are advantageous in that they allow access to machinery to be controlled in such a way that access is allowed only when such access can be safely allowed, they are disadvantageous in that users must be provided with relevant codes, and further disadvantageous in that each cell is effectively provided with a stand-alone access control system over which there is no centralised control and management.